Roberto Martínez believes guiding Wigan Athletic into the first FA Cup final in the club's history will be a hollow achievement should they fail to stay in the Premier League.

Wigan visit Manchester City in a dress rehearsal of the Wembley final on Wednesday immersed in relegation trouble, with the third-from-bottom club three points adrift of Aston Villa but with two games in hand. Martínez admits his team has added confidence and competitive edge following Saturday's FA Cup semi-final defeat of Millwall, with the squad fighting for places on 11 May, but he will not deem the season a success if Wigan fail to remain in the Premier League for a ninth consecutive season.

"We're not going to hide the fact that we have to achieve our aim in the league to feel we have had a successful season," the Wigan manager said. "I'm not going to deflect from that and try and hide behind the fact our FA Cup campaign has been a real success. The season will not be a success unless we achieve our aim in the league. To reach the targets we have on and off the pitch we need to stay in this league."

Martínez admits the league meeting with City has greater implications for Wigan's future than a historic first appearance in an FA Cup final next month. "In many aspects the league game is bigger," he added. "I don't think there are games which are more important than others. They are all very significant. But if you are asking me what it represents for a club like Wigan winning the FA Cup final or staying in the Premier League, then staying in the Premier League would mean the next 10 years of the football club would be financially very stable. The new facilities that we have planned can happen and behind the scenes the club can go to a different level.

"But when you have the opportunity to win the FA Cup, you can't disregard it and say that's not important. They are both important. This is the sort of season we want. There's only Manchester City, Chelsea and Wigan who are involved in two competitions at this moment. It requires a strong mentality and we've never had that before."

Wigan's comfortable semi-final win was overshadowed by the fighting that occurred between some Millwall supporters but Martínez insists the victors were not resentful. "At Wigan you learn quickly that you don't do things to get credit, otherwise you would be pulling your hair out every day," he said. "But there is a lot of internal satisfaction."

And the Wigan manager is confident he has the resources to cope with a relegation battle and FA Cup final over the next five weeks. He explained: "You run a risk if you rely on 12 or 13 players. That's 100%. We've now got a pool of 17 or 18 players who have been playing consistently and with that number we can face two competitions, no problem."